Go back
Math question

Math question

General

2 edits
Vote Up
Vote Down

Originally posted by Nordlys
I am not sure what the "6 C 2" means, but yes, 15 is right. Every player has to play five games, so that's 30 games divided by 2 because there are always two players involved.
the C is short for combination, and the P in his first post referred to permutation.

combination is where the order doesn't matter. e.g. {abc}={bca}={cba}..., while in a combination the order does matter, {abc} does not equal {bca}.

the formulas are,
n P r=P(n,r)=n!/[(n-r)!]

n C r=C(n,r)=n!/[r!(n-r)!]

in the example here, the order does not matter. 1A=A1.

8 C 8=8!/0!=8!

1 edit
Vote Up
Vote Down

😠

Vote Up
Vote Down

Originally posted by RahimK
Just to refresh my memory:

If you have 8 proffessors and 8 offices and you have to assign each to 1 office how many different ways are there?

8 P 8 = 40, 320 or 8! = 40, 320.

This is it right?



Just a sidenote here which I was thinking about. You have a chess tourney and you have 6 players and it's a round robin. How many total games?

6 C 2 = 15 right?
Just 1

Because you are in charge and get to make the selection!

Harri / Luck

Vote Up
Vote Down

Originally posted by Luck
Just 1

Because you are in charge and get to make the selection!

Harri / Luck
zero, as none of the professors ever show up in their offices...

1 edit
Vote Up
Vote Down

Originally posted by genius
8 C 8=8!/0!=8!
Nope.

If the order is irrelevant, then you only have one way to group 8 elements in groups of 8

8 C 8 = 8!/(8!*0!)=1

Vote Up
Vote Down

Originally posted by genius
the C is short for combination, and the P in his first post referred to permutation.
Thanks. I had combinatorial analysis in highschool, so I know what combinations and permutations are, I am just not familiar with that way of writing it.

Vote Up
Vote Down

Originally posted by wormwood
zero, as none of the professors ever show up in their offices...
They will show up during their scheduled office hours.
The easiest (and just about the only way) way to remove permanent academic staff from the university is to complain that they are not in the office during their scheduled hours.
They may not spend a lot of time of the campus, but tehy will respect the stated office hours or they will get fired!

Harri / Luck

Vote Up
Vote Down

Originally posted by Nordlys
I am just not familiar with that way of writing it.
yea, I think it's the north american way. they have weird notation for integrals as well, which always throws me off...

Vote Up
Vote Down

Originally posted by wormwood
yea, I think it's the north american way. they have weird notation for integrals as well, which always throws me off...
How do you note it without upper and lower indexes?

Vote Up
Vote Down

Originally posted by Palynka
Nope.

If the order is irrelevant, then you only have one way to group 8 elements in groups of 8

8 C 8 = 8!/(8!*0!)=1
not sure what i was thinking when i said that. 8!*0!=1? hmm...😳